I'm trying to figure out a way to multiplex three circuits(12V, 0.5A MAX) using 2 LEDs from a DSP evaluation kit as the decoder bits. When the LEDs turn on, the voltage change is a little over 1V (2.5 - 3.6). I'm stumped as to what to do with these specifications. Any help would be appreciated. Thank you!

btw, These three circuits are used to control fan speeds on a standard 12V fan.